event notifier

src/shared/eventNotifier.test.ts

@@ -0,0 +1,145 @@
+import { createEventNotifier } from "./eventNotifier.js";
+
+describe("EventNotifier", () => {
+  let notifier: ReturnType<typeof createEventNotifier<string>>;
+
+  beforeEach(() => {
+    notifier = createEventNotifier<string>();
+  });
+
+  test("should notify listeners in registration order", () => {
+    const events: string[] = [];
+    notifier.onEvent((event) => events.push(`first: ${event}`));
+    notifier.onEvent((event) => events.push(`second: ${event}`));
+    notifier.onEvent((event) => events.push(`third: ${event}`));
+
+    notifier.notify("test event");
+
+    expect(events).toEqual([
+      "first: test event",
+      "second: test event",
+      "third: test event",
+    ]);
+  });
+
+  test("should not notify unsubscribed listeners", () => {
+    const events: string[] = [];
+    const subscription = notifier.onEvent((event) => events.push(event));
+
+    notifier.notify("first event");
+    subscription.close();
+    notifier.notify("second event");
+
+    expect(events).toEqual(["first event"]);
+  });
+
+  test("should handle function events", () => {
+    const events: string[] = [];
+    notifier.onEvent((event) => events.push(event));
+
+    notifier.notify(() => "dynamic event");
+
+    expect(events).toEqual(["dynamic event"]);
+  });
+
+  test("should handle errors through error handler", () => {
+    const errors: Error[] = [];
+    notifier.onError((error) => errors.push(error));
+
+    notifier.onEvent(() => {
+      throw new Error("test error");
+    });
+
+    notifier.notify("test event");
+
+    expect(errors).toHaveLength(1);
+    expect(errors[0]).toBeInstanceOf(Error);
+    expect(errors[0].message).toBe("test error");
+  });
+
+  test("should not notify after close", () => {
+    const events: string[] = [];
+    notifier.onEvent((event) => events.push(event));
+
+    notifier.notify("first event");
+    notifier.close();
+    notifier.notify("second event");
+
+    expect(events).toEqual(["first event"]);
+  });
+
+  test("should handle multiple subscriptions and unsubscriptions", () => {
+    const events: string[] = [];
+    const subscription1 = notifier.onEvent((event) =>
+      events.push(`1: ${event}`)
+    );
+    const subscription2 = notifier.onEvent((event) =>
+      events.push(`2: ${event}`)
+    );
+
+    notifier.notify("first event");
+    subscription1.close();
+    notifier.notify("second event");
+    subscription2.close();
+    notifier.notify("third event");
+
+    expect(events).toEqual([
+      "1: first event",
+      "2: first event",
+      "2: second event",
+    ]);
+  });
+
+  test("should handle error handler after close", () => {
+    const errors: Error[] = [];
+    notifier.onError((error) => errors.push(error));
+    notifier.close();
+
+    notifier.onEvent(() => {
+      throw new Error("test error");
+    });
+
+    notifier.notify("test event");
+
+    expect(errors).toHaveLength(0);
+  });
+
+  test("should clear error handler on close", () => {
+    const errors: Error[] = [];
+    notifier.onError((error) => errors.push(error));
+
+    // Close should clear the error handler
+    notifier.close();
+
+    // Setting up a new listener after close
+    notifier.onEvent(() => {
+      throw new Error("test error");
+    });
+
+    // This should not trigger the error handler since the notifier is closed
+    notifier.notify("test event");
+
+    expect(errors).toHaveLength(0);
+  });
+
+  test("should use the last set error handler", () => {
+    const errors1: Error[] = [];
+    const errors2: Error[] = [];
+
+    // First error handler
+    notifier.onError((error) => errors1.push(error));
+
+    // Second error handler should replace the first one
+    notifier.onError((error) => errors2.push(error));
+
+    notifier.onEvent(() => {
+      throw new Error("test error");
+    });
+
+    notifier.notify("test event");
+
+    expect(errors1).toHaveLength(0);
+    expect(errors2).toHaveLength(1);
+    expect(errors2[0].message).toBe("test error");
+  });
+});